WO2019046870A1

WO2019046870A1 - Determination of the ranking of the perception intensity of stimuli from a test set of stimuli in a test person

Info

Publication number: WO2019046870A1
Application number: PCT/AT2018/060145
Authority: WO
Inventors: Christoph GUGER; Günter EDLINGER
Original assignee: Guger Christoph; Edlinger Guenter
Priority date: 2017-09-06
Filing date: 2018-07-11
Publication date: 2019-03-14
Also published as: AT520374B1; AT520374A1

Abstract

The invention relates to a method for determining the ranking of the perception intensity of stimuli (S1,...,Sn) from a test set of stimuli in a test person (1) by means of a brain-computer interface (20), wherein a reference set of stimuli (Z, V1,..., Vn) is compiled from at least one target stimulus (Z) and a predefined number of comparison stimuli (V1,..., Vn), wherein in a training phase a) the individual stimuli (Z, V1,..., Vn) from the reference set are applied to the test person (1), b) wherein after the application of every stimulus (Z, V1,..., Vn) from the reference set the reaction of the test person (1) is ascertained in that the (1) EEG measurement data (U1,..., Un) of the test person caused by the stimulus (Z, V1,..., Vn) or having a time relationship with said stimulus are determined, and these EEG measurement data (U1,..., Un) are assigned to the respective stimuli (Z, V1,..., Vn), wherein for each stimulus (Z, V1,..., Vn) at least one characteristic vector is created from the EEG measurement data (U1,..., Un) of all EEG channels, and c) wherein the characteristic vectors, obtained in this way, of the stimuli (Z, V1,..., Vn) from the reference set undergo a classification analysis, wherein a differentiation function (F) is determined to delimit the set of characteristic vectors of the comparison stimuli (V1,..., Vn) from the set of characteristic vectors of the target stimulus (Z), wherein the differentiation factor specifies whether a stimulus (Z, V1,..., Vn) is a target stimulus (Z) or a comparison stimulus (V1,..., Vn). In an investigation phase d) a test set of stimuli (S1,..., Sm) is applied to the test person (1), wherein the test set comprises stimuli (S1,..., Sm) at least some of which or all of which differ from the stimuli (Z, V1,..., Vn) of the reference set, e) wherein after the application of every stimulus (S1,..., Sm) of the test set the EEG measurement data (U1,..., Un) of the test person (1) are determined in the same way as in step b) and on the basis of the EEG measurement data (U1,..., Un) a characteristic vector is first created for each stimulus (S1,..., Sm) and f) wherein the differentiation function (F) is applied to the characteristic vector of each individual stimulus (S1,..., Sm) of the test set and thus a first measurement value is determined for matching each stimulus (S1,..., Sm) of the test set to the target stimulus (Z) of the reference set, and g) wherein a ranking of the perception intensity of the stimuli (S1,..., Sm) of the test set is created according to the first measurement value for matching to the target stimulus (Z) of the reference set.

Description

Determination of the ranking of the perception intensity of stimuli from a

Test amount of stimuli in a subject

The invention relates to a method according to the preamble of claim 1.

From the prior art, a variety of different methods for determining the perception or perception quality of subjects known, all of these methods apply different types of stimuli to the subjects and is tested on the basis of the reaction of the subject in the form of brain waves, whether the subject in question shows adequate mental activity due to the stimuli or not. Also known from the prior art are individual, so-called brain computer interfaces, with which the processes occurring inside the brain of a person can be determined, further processed and also visualized in different ways. These known methods are often used to determine in subjects with no ability to communicate through speech, gestures, etc., whether a subject can perceive a stimulus at all.

From the prior art, however, no methods are known which are used in subjects, in particular advertisers, with potentially unlimited cognitive ability stimuli according to their perceptual intensity, in particular the measured subjective impressiveness, the subject starting from the EEG measurement data of the subject during the application of stimuli, to evaluate.

The object of the invention is therefore to provide a rapid and simple method which makes it possible to effectively determine the perceptual intensity of each individual stimulus from a group of stimuli in a subject and, based on this, to establish a ranking of the stimuli according to the perceptual intensity.

The invention solves this problem in a method for determining the ranking of the perception intensity of stimuli from a test amount of stimuli in a subject by means of a brain-computer interface with the features specified in the characterizing part of claim 1. It is provided that a reference set of stimuli is composed of at least one target stimulus and a predetermined number of comparison stimuli, wherein in a training phase

a) the individual stimuli from the reference quantity are applied to the subject, b) after the application of each stimulus from the reference set, the respondent's response is determined by determining the subject's EEG measurement data produced by the stimulus or associated with that temporal, and assigning that EEG measurement data to the respective stimulus, wherein for each stimulus, at least one feature vector is created from the EEG measurement data of all EEG channels, and

c) subjecting the feature vectors of the stimuli thus obtained to a classification analysis from the reference set, wherein a distinguishing function for delimiting the set of feature vectors of the comparison stimuli from the set of feature vectors of the target stimulus is determined, the distinguishing function indicates whether a stimulus is a target stimulus or a comparative stimulus, and where in an investigation phase

d) a test quantity of stimuli is applied to the subject, the test quantity comprising stimuli that are at least partially or entirely different from the stimuli of the reference quantity,

e) wherein after application of each stimulus of the test set in the same manner as in step b) the EEG measurement data of the subject are determined and based on the EEG measurement data for each stimulus first a feature vector is created and f) wherein each of the distinguishing function on the feature vector of each individual stimulus of the test set is applied, and thus a first measure of the correspondence of each stimulus of the test set with the target stimulus of the reference set is determined, and

g) wherein a ranking of the perceptual intensity of the stimuli of the test set is established according to the first measure of correspondence with the target stimulus of the reference set.

A particularly advantageous analysis of the EEG measurement data can be achieved by subjecting the feature vectors of the stimuli of the reference set to one of the following types of classification analysis:

- Discriminant analysis, in particular linear discriminant analysis,

- Support vector machines,

- neural networks,

- other discrimination functions.

A particularly simple evaluation of the values obtained for the individual stimuli for the generation of a ranking is ensured if the stimulus of the Test set with the highest match with the target stimulus of the reference set corresponds to the stimulus with the highest perceived intensity.

An alternative to determining the measure value is provided by specifying the distance from a discriminating line or level of discrimination indicated by the discriminating function.

To improve the reliability of the measured values obtained for the individual stimuli, it is provided that each stimulus from the test quantity is applied several times to the test person and that the mean value of the measurement values from all applications of each individual stimulus is used in determining the ranking of the perception intensity or Measured values from all applications of each stimulus are used.

In order to advantageously already make a statement in the training phase as to how meaningful the classification analysis is with respect to the distinction of the target stimulus from the comparison stimuli, it is provided that in the training phase a measure of the probability of delimiting the set of feature vectors the comparison stimuli of the set of feature vectors of the target stimulus is determined by the distinguishing function, in particular that when falling below a predetermined threshold probability or threshold accuracy of the delineation, the method is aborted.

In order to check whether a sufficiently meaningful differentiation of the target stimulus from the comparison stimuli is possible by means of the determined distinguishing function, it is provided that feature vectors for the individual stimuli of the reference set are repeatedly created in the training phase, the feature vectors of each individual Stimulus of the reference set from all repetitions of a classification analysis are subjected, and a distinguishing function for delimiting the set of feature vectors of the comparison stimuli of the set of feature vectors of the target stimulus is determined, and that after each repetition or each after a number of repetitions, the discriminating function is applied to the feature vector of each individual stimulus of the reference set and it is checked whether the obtained demarcation of the set of feature vectors of the comparison stimuli from the set of feature vectors of the target stimulus (Z) pre-admit NEN accuracy is sufficient. As an alternative variant of a method for determining the ranking of the perception intensity of stimuli in a subject by means of a brain-computer interface is provided that

a) the individual stimuli from the test set are applied to the subject, b) wherein after the application of each stimulus from the test set the response of the subject is determined by the caused by the stimulus or temporally related EEG measurement data of the subject are determined with a predetermined number of EEG channels, and these EEG measurement data are assigned to the respective stimulus, wherein an evoked potential for each individual stimulus is determined as the mean value of the EEG measurement data from the predetermined number of EEG channels, and

c) wherein the order of magnitude of the perception intensity of the stimuli of the test set is determined from a second measurement value, which is determined in particular according to the amplitude of the evoked potentials derived from the EEG measurement data, wherein a higher amplitude indicates a higher perception intensity.

A particularly simple evaluation of the values obtained for the individual stimuli from the evoked potentials for establishing a ranking is ensured if the stimulus of the test set having the highest determined amplitude of the associated evoked potential corresponds to the stimulus having the highest perception intensity.

A particularly meaningful variant of a method for determining the order of perceived intensity of stimuli in a subject is to rank the intensity of perception of the stimuli from the test set by the area under the evoked potential curve, with a large area under the curve providing a high perceptual intensity indexed, and / or after the latency of the evoked potential, wherein a short latency indicates a high perceptual intensity, is determined.

In order to be able to evaluate the measurement values for the individual stimuli obtained with different evaluation methods simply with regard to the generation of a ranking order of the perception intensity, it is provided that a first dimension value and additionally a second dimension value are determined in the investigation phase for determining the ranking of the perception intensity of the stimuli from the test set In order to determine the order of priority of the perception intensity of the stimuli, a common measured value is determined from the two determined dimensional values. An alternative method of evaluating the evoked potentials associated with a stimulus is advantageously provided by indexing the greater the perceptual intensity the greater the first measure value indicated match of the stimulus from the test set to the target stimulus of the reference set and the greater is the intensity of perception indicated by the second measure.

A reliable determination of the perceptual intensity of a stimulus is ensured by applying the individual stimuli from the reference set and / or the individual stimuli from the test set to the subject sequentially in time, with each individual stimulus from the reference set and / or to each individual stimulus the test quantity follows an application-free period.

Since the brain carries out mental activities even without the presence of a stimulus, which are comprehensible in the EEG measurement data, the EEG measurement data, which can only be attributed to the respective stimulus, is intended to be distinguished within a fixed temporal reference interval before the application of each stimulus a voltage offset value is determined from the reference quantity and / or before the application of each stimulus, and the voltage offset value is subtracted from the EEG measurement data associated with the respective stimulus from the reference quantity and / or from the test quantity associated with the respective stimulus.

In order to make the perceptual intensities of the individual stimuli from the test amount of stimuli in a test subject comparable with one another, as similar as possible prescriptions for the application of the stimuli to the test subject are advantageous. A good comparability of the perceptual intensity of the individual stimuli is advantageously ensured by specifying an application duration for each individual stimulus from the reference quantity and / or for each individual stimulus from the test set, in particular that an equally long application duration is specified for all stimuli, and / or that a number of repetitions for each individual stimulus from the reference amount and / or for each individual stimulus from the test set is given, in particular that all stimuli are repeated with the same number of repetitions, and / or that the duration of the application-free period after given to each individual stimulus from the reference set and / or after each individual stimulus from the test set, in particular, that for all / before all stimuli an equal duration of the application-free period is specified.

A particularly advantageous embodiment of the invention for establishing a ranking of the perception intensity of different types of stimuli Impressions, provides that the stimuli from the reference set and the stimuli from the test set stimuli of at least one of the following types:

- visual stimuli, in particular images, in particular with a display duration shorter than 2000 ms, preferably shorter than 500 ms, and / or greater than 100 ms, which are presented to the subject by means of a screen, and / or

auditory stimuli or sounds in human audible frequencies, in particular sequences of sounds, preferably with a total duration shorter than 2000 ms, preferably shorter than 500 ms, and / or greater than 100 ms, the respective sounds being played back to the subject, and /or

- Vibrotaktile stimuli to different body parts, in particular with a duration shorter than 2000 ms, preferably shorter than 500 ms, and / or greater than 100 ms, which are applied to the subject by means of vibration units, and / or

- Electrical stimuli to different parts of the body, in particular with a duration shorter than 2000 ms, preferably shorter than 500 ms, and / or greater than 100 ms, which are applied to the subject by means of electrical stimulators, and / or

the application of different words, in particular names, preferably with a duration shorter than 2000 ms, preferably shorter than 1000 ms, and / or greater than 100 ms, the application being that the respective words are played to the subject and / or predicted and / or displayed.

Furthermore, according to the invention, a device is provided for determining the ranking of the perception intensity of stimuli from a test set of stimuli in a subject, comprising

an electrode cap comprising a number of EEG electrodes,

- A the electrode hood downstream brain-computer interface, wherein the brain-computer interface is adapted to measure each of the voltage applied to the EEG electrodes voltages and to provide measurement results as EEG measurement data available

- A brain-computer interface downstream control unit and

at least one stimulation unit connected downstream of the control unit, wherein in the control unit control instructions for the stimulation unit for applying a reference amount of stimuli composed of at least one target stimulus and a predetermined number of comparison stimuli and a test amount of stimuli are deposited, wherein the test amount at least partially or entirely different from the stimuli of the reference amount Stimuli includes, and wherein the control unit is adapted to, in a training phase

to control the stimulation unit and to apply the individual stimuli from the reference quantity to the subject via the stimulation unit,

provide the stimulus, or the subject's EEG measurement data provided by the brain-computer interface, after the application, to associate each stimulus from the reference set with the respective stimulus and thus determine the respondent's response,

for each stimulus at least one feature vector from the EEG measurement data of all

To create EEG channels and

to subject the thus obtained feature vectors of the stimuli from the reference set to a classification analysis and to determine a discrimination function for delimiting the set of feature vectors of the comparison stimuli from the set of feature vectors of the target stimulus, the discrimination function indicating whether a stimulus is a target stimulus or a comparative stimulus, and wherein the control unit is adapted to

in an investigation phase

to control the stimulation unit and to apply the test amount of stimuli to the subject via the stimulation unit,

provide the stimulus, or the subject's EEG measurement data provided by the brain-computer interface, after the application, to associate each stimulus from the test set with the respective stimulus and thus determine the respondent's response,

to generate for each stimulus at least one feature vector from the EEG measurement data of all EEG channels,

apply the discriminator function to the feature vector of each individual stimulus of the test set to determine a first measure of the correspondence of each stimulus of the test set to the target stimulus of the reference set, and

to create a ranking of the perceptual intensity of the stimuli of the test set corresponding to the first measure of agreement with the target stimulus of the reference set. A particularly advantageous analysis of the EEG measurement data is ensured by the fact that the control unit is designed to subject the feature vectors of the stimuli of the reference quantity to one of the following types of classification analysis:

- Discriminant analysis, in particular linear discriminant analysis,

- Support vector machines,

- neural networks,

- other discrimination functions.

For a particularly simple evaluation of the values obtained for the individual stimuli for generating a ranking, it is provided that the control unit is adapted to the stimulus of the test set with the highest match with the target stimulus of the reference set as the stimulus with the highest perceptual intensity to identify.

For an alternative determination of the dimensional value, it is provided that the control unit is designed to determine the distance from a discrimination straight line or discrimination level specified by the distinguishing function as a dimensional value.

An improvement in the reliability of the measured values obtained for the individual stimuli is achieved if the control unit is designed to control the stimulation unit, to apply each stimulus from the test quantity several times to the subject, and in the determination of the ranking of the perceptual intensity to average the values of all Apply applications of each stimulus or the measures from all applications of each stimulus.

In order to advantageously already make a statement in the training phase as to how meaningful the classification analysis is with respect to the distinction of the target stimulus from the comparison stimuli, it is provided that the control unit is designed in the training phase a measure of the probability of demarcation the set of feature vectors of the comparison stimuli of the set of feature vectors of the target stimulus to be determined by the distinguishing function, in particular that the control unit is adapted to fall below a predetermined threshold probability or threshold accuracy of the delimitation To trigger stimulation unit and deliver a warning about the stimulation unit, in particular to end the training phase. In order to check whether a sufficiently meaningful differentiation of the target stimulus from the comparison stimuli is possible by means of the determined distinguishing function, it is provided that the control unit is designed to repeat in the training phase:

to apply the stimuli from the reference quantity to the subject via the stimulation unit,

Feature vectors for each stimulus of the reference set to create the feature vectors of each stimulus of the reference set from all

Subject repetitions to a classification analysis,

determine a discrimination function for discriminating the set of feature vectors of the comparison stimuli from the set of feature vectors of the target stimulus, and

after each repetition, apply the discriminating function to the feature vector of each individual stimulus of the reference set and verify that the achieved demarcation of the set of feature vectors of the comparison stimuli from the set of feature vectors of the target stimulus satisfies a predetermined accuracy ,

An alternative device for determining the ranking of the perceptual intensity of stimuli from a test set of stimuli in a subject

an electrode cap comprising a number of EEG electrodes,

- A brain-computer interface downstream control unit and

- At least one of the control unit downstream stimulation unit

According to the invention, control instructions for the stimulation unit for applying a test amount of stimuli are stored in the control unit, and the control unit is designed to:

to control the stimulation unit and to apply the individual stimuli from the test quantity to the subject via the stimulation unit,

provide the stimulus, or the subject's EEG measurement data provided by the brain-computer interface, after the application, to associate each stimulus from the test set with the respective stimulus and thus determine the response of the subject; to determine the ranking of the perceptual intensity of the stimuli of the test set to determine a second measure, in particular according to the amplitude of the evoked potentials derived from the EEG measurement data, wherein a higher amplitude indicates a higher perceptual intensity.

For a particularly simple evaluation of the values obtained for the individual stimuli from the evoked potentials for generating a ranking, it is provided that the control unit is adapted to that stimulus of the test set having the highest determined amplitude of the associated evoked potential as the stimulus with the highest perceptual intensity identify.

As an alternative evaluation for determining the ranking of the perception intensity of stimuli in a subject, it is provided that the control unit is designed to determine the order of magnitude of the perception intensity of the stimuli from the test set according to the area under the evoked potential curve, with a large area under indicates a high perceptual intensity to the curve, and / or to determine the latency of the evoked potential, where a short latency indicates a high perceptual intensity.

In order to be able to evaluate the values for the individual stimuli obtained with different evaluation methods simply with regard to the generation of a ranking of the perception intensity, it is provided that the control unit is designed to determine a first measure value in the examination phase for determining the order of the intensity of perception of the stimuli from the test set by applying the discriminating function to the feature vector of each stimulus of the test set and additionally determining a second measure, in particular the amplitude of the evoked potentials derived from the EEG measurement data, and determining a common measure of the order of magnitude of the perceptual intensity of the stimuli to determine the two measured values.

For the alternative evaluation of the evoked potentials associated with a stimulus, it is advantageously provided that the control unit identifies the greater the perception intensity of the common measurement value, the greater the indexed stimulus of the test quantity with the target stimulus of the reference quantity and the greater indicated by the first measurement value is the intensity of perception indicated by the second measure. A reliable determination of the perception intensity of a stimulus is ensured by the control unit being designed to control the stimulation unit, to apply the individual stimuli from the reference set and / or the individual stimuli from the test set to the subject sequentially in time, and to each individual stimulus from the reference amount and / or to follow each stimulus from the test amount an application-free period.

Since the brain executes mental activities even without the presence of a stimulus, which are comprehensible in the EEG measurement data, the brain-computer interface is provided with a voltage offset unit for better delineation of the EEG measurement data that can only be attributed to the respective stimulus comprising, wherein the voltage-offset unit is adapted to determine a voltage offset value and the voltage offset value in a fixed time reference interval before the application of each stimulus from the reference amount and / or before the application of each stimulus from the test set subtract from the EEG measurement data associated with the respective stimulus from the reference set and / or the stimulus from the test set.

In order to ensure a good comparability of the perceptual intensity of the individual stimuli, it is provided that the control unit is designed to predetermine an application duration for each individual stimulus from the reference quantity and / or for each individual stimulus from the test quantity, in particular that the control unit presets an equal long application duration is designed for all stimuli, and / or that the control unit is designed to specify a number of repetitions for each individual stimulus from the reference quantity and / or for each individual stimulus from the test quantity, in particular that the control unit presets an equal number is formed on repetitions for all stimuli, and / or that the control unit is designed to predetermine a duration of the application-free period after each individual stimulus from the reference quantity and / or after each individual stimulus from the test quantity, in particular, that the control unit to Vorg abe an equally long duration of the application-free period after all stimuli is formed.

A particularly advantageous embodiment of the invention for establishing a ranking of the perception intensity of different types of stimuli impresses, provides that the stimulation unit is designed to apply stimuli of at least one of the following types: visual stimuli, in particular images, in particular with a display duration shorter than 2000 ms, preferably shorter than 500 ms, and / or greater than 100 ms, and / or auditory stimuli or sounds in frequencies audible to a human, in particular sequences of sounds, preferably with a total duration shorter than 2000 ms, preferably shorter than 500 ms, and / or greater than 100 ms, and / or vibrotactile stimuli on different body parts, in particular with a duration shorter than 2000 ms, preferably shorter than 500 ms, and / or greater as 100 ms, and / or

electrical stimuli to different body parts, in particular with a duration shorter than 2000 ms, preferably shorter than 500 ms, and / or greater than 100 ms, and / or

the application of different words, in particular names, preferably with a duration shorter than 2000 ms, preferably shorter than 1000 ms, and / or greater than 100 ms.

Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings.

Particularly advantageous, but not limiting, embodiments of the invention are illustrated schematically below with reference to the accompanying drawings and described by way of example with reference to the drawings:

In Fig. 1 shows schematically a subject and an arrangement for the measurement and further processing of EEG measurement data. Fig. 2 shows a reference set of stimuli. Fig. 3 shows voltage signals which were determined by means of EEG electrodes. Fig. 4 schematically shows a result of a classification analysis for the reference set of stimuli. Fig. 5 shows a test amount of stimuli. Fig. 6 shows schematically the feature vectors of the stimuli from the test set plotted in a feature space. 7 shows diagrammatically evoked potentials for the test amount of stimuli derived from the EEG measurement data.

In Fig. 1, a subject 1 is shown sitting on a chair. On the head of the subject 1 there are EEG electrodes 21-24, wherein the EEG electrodes 21-24 are connected to an EEG processing device 2. The arrangement comprising the individual EEG electrodes 21-24 and the EEG measuring unit 2 represents a brain-computer interface 20. This brain-computer interface 20 is connected to a test and test computer Control unit 30 is connected, which controls a screen 40 in the present embodiment of the invention.

As a first step of a first embodiment of a method according to the invention, individual stimuli from a reference set of stimuli are applied to the subjects 1 in a training phase in chronological succession, with an application-free period following each stimulus. For this purpose, the screen 40 is controlled by the control unit 30 such that the subject 1 in the illustrated embodiment, images are presented as stimuli. In the exemplary embodiment, the individual stimuli from the reference quantity of stimuli are repeatedly applied to the subject 1.

Fig. 2 shows a reference set of stimuli, which in the first embodiment consists of five images, is composed of a target stimulus Z and a number of four comparison stimuli i, V ₂ , V ₃ , V ₄ . The target stimulus Z in the illustrated example is an image of a bar of chocolate, while the four comparison stimuli V _{1 5} V ₂ , V ₃ , V _{4 represent} gray-white patterns.

After the application of each stimulus Z, V _{1 5} V ₂ , V ₃ , V ₄ from the reference amount of the reaction of the subject 1 is detected. For this purpose, the EEG processing device 2 evaluates the individual brain waves emitted by the subject 1 and uses these brain waves to generate the EEG measurement data Ui, U ₂ , U temporally related to each stimulus Z, V _{1 5} V ₂ , V ₃ , V ₄ ₃ , U _{4 of} all EEG channels or EEG electrodes 21-24. Different preprocessing and filtering methods can be used.

Ultimately, EEG measurement data Ui, U ₂ , U ₃ , U _{4 are available} as a result of measured voltage signals, each of the voltage signals indicating a voltage value for a plurality of times. 3 schematically shows the time profile of the EEG measurement data DU ₂ , U ₃ , U ₄ for a stimulus wherein the voltage signals in the illustrated example can be subdivided into three temporal intervals: a reference time interval R 1, which describes a time period before the application of a stimulus , an application period A, during which a stimulus is applied to the subject 1, a reaction period R and an application-free period AF.

The reference interval before the application of each stimulus Z, V _{1 5} V ₂ , V ₃ , V ₄ from the reference set or a stimulus S _{1 5} S ₂ , S ₃ , S ₄ , S ₅ from a test set of stimuli In all variants of a method according to the invention, it can be used to determine a voltage offset value which describes the brain waves emitted by the subject 1 without the application of a stimulus. This voltage offset value can be used as a correction value for the EEG measured data Ui, U ₂ , U ₃ assigned to a stimulus Z, V _{1 5} V ₂ , V ₃ , V ₄ or Si, S ₂ , S ₃ , S ₄ , S ₅ , U _{4 are} used in order to be able to evaluate more easily the brain waves attributable directly to the application of a stimulus Z, V _{1 5} V ₂ , V ₃ , V ₄ or Si, S ₂ , S ₃ , S ₄ , S ₅ .

As the next step of a method according to the invention, for each stimulus Z, V _{1 5} V ₂ , V ₃ , V _4, a feature vector is obtained from the reference quantity from the EEG measurement data DU ₂ , U ₃ , U ₄ thus processed and assigned to the respective stimulus created. For example, when generating a feature vector, the average values or mean signal energy of individual EEG channels from partial periods of the application period can be used from all EEG channels.

In the present case, for example, for every stimulus Z, V _{1 5} V ₂ , V ₃ , V ₄ from the reference quantity, all four data sets of EEG measurement data DU ₂ , U ₃ , U _{4 of} the EEG electrodes 21 - 24 are measured in each case via eight Partial periods used so that the corresponding to a stimulus Z, V _{1 5} V ₂ , V ₃ , V ₄ belonging to the reference set feature vector has a total of 32 components. The thus obtained feature vectors of the stimuli Z, V _{1 5} V ₂ , V ₃ , V ₄ from the reference set are subjected to a classification analysis.

4 schematically shows the result of a linear discriminant analysis for the feature vectors of the stimuli Z, V _{1 5} V ₂ , V ₃ , V ₄ from the reference set, which in the example are plotted in a two-dimensional feature space. Alternatively, a classification analysis by means of z. Support vector machines, neural networks or other discrimination functions.

In the example, each stimulus Z, V _{1 5} V ₂ , V ₃ , V ₄ from the reference set was applied eight times to the subject 1, so that for each stimulus Z, V _{1 5} V ₂ , V ₃ , V ₄ eight feature vectors be available.

To delineate the set of feature vectors of the comparison stimuli V _{1 5} V ₂ , V ₃ , V ₄ from the set of feature vectors of the target stimulus Z, a discrimination function F is determined by means of linear discriminant analysis, which indicates whether a stimulus is a target stimulus Z or a comparative stimulus V _{1 5} V ₂ , V ₃ , V ₄ . Here is the Discriminating function F is determined so that the set of feature vectors of the target stimulus Z and the set of feature vectors of the comparison stimuli V _{1 5} V ₂ , V ₃ , V _{4 are} optimally separated. The distinguishing function F is given in the example in FIG. 4 as a linear function.

Furthermore, by means of the classification analysis, a measure of the probability and a measure of the accuracy is determined so that the distinguishing function F determines the set of feature vectors of the comparison stimuli V _{1 5} V ₂ , V ₃ , V ₄ from the set of feature values. Vectors of the target stimulus Z can separate. The higher the measured value, the more likely a reliable separation of the two feature vector groups.

If a predetermined threshold probability or threshold accuracy of a reliable separation of the two feature vector groups is exceeded, a method according to the invention is advantageously aborted, since in this case not reliable statements on the order of the perception intensity of stimuli S _{1 5} S ₂ , S ₃ , S ₄ , S ₅ , is to be expected from a test amount. In this case, a warning message is advantageously issued. This is the case, for example, if the target stimulus and the comparative stimuli Z, V _{1 5} V ₂ , V ₃ , V ₄ are chosen to be too similar from the reference set and no discriminant function F can be found by means of the linear discriminant analysis gives a satisfactory separation of the two feature vector groups.

In the training phase, a check of the discriminator function F or of the weight vector indicating the separation line, the set of feature vectors of the target stimulus Z and the set of feature vectors of the comparison stimuli V _{1 5} V ₂ , V ₃ , V ₄ optimally separates, be provided. For this purpose, for example, the stimuli Z, V _{1 5} V ₂ , V ₃ , V _{4 of} the reference quantity applied again to the subjects 1, after the application of each stimulus Z, V _{1 5} V ₂ , V ₃ , V _4, the reaction of the subject. 1 again determined and with each stimulus Z, V _{1 5} V ₂ , V ₃ , V ₄ temporally related EEG measured data DU ₂ , U ₃ , U ₄ determined.

From the thus processed and the respective stimulus associated EEG measurement data U _{1 5} U ₂ , U ₃ , U ₄ , a feature vector is created, to which the distinguishing function F is applied. This can be done, for example, by forming the scalar product from the feature vector and the weight vector. It is then checked whether the separation between the set of feature vectors of the target stimulus Z and the set of feature vectors of the comparison stimuli Vi, V ₂ , V ₃ , V ₄ is ensured by applying the weight vector with a predetermined accuracy ,

This check can also be carried out repeatedly, so that an increasing number of feature vectors of the target stimulus Z and feature vectors of the comparison stimuli V _{1 5} V ₂ , V ₃ , V ₄ are available with each repetition, and the means of the Classification analysis F is adapted with each iteration, whereby the accuracy of the separation is gradually increased.

After each repetition or each time after a number of repetitions, the most recently determined distinguishing function F is applied to the feature vector of each individual stimulus Z, V ₁ ..., V _{n of} the reference set. In this way, it is checked whether the achieved delimitation of the set of feature vectors of the comparison stimuli from the set of feature vectors of the target stimulus Z satisfies a predetermined accuracy.

In the next step of a first embodiment of a method according to the invention, a test set of stimuli Si, S ₂ , S ₃ , S ₄ , S _{5 is} applied to the subjects 1 in an examination phase. In the described exemplary embodiment, the stimuli Si, S ₂ , S ₃ , S ₄ , S _{5 of} the test set are applied successively to the subject 1, with an application-free period of time for each stimulus Si, S ₂ , S ₃ , S ₄ , S ₅ follows.

In the example, for the stimuli Si, S ₂ , S ₃ , S ₄ , S ₅ from the test set, the application time, the number of repetitions, and the duration of the application-free period after each stimulus Si, S ₂ , S ₃ , S ₄ , S ₅ advantageously chosen the same as for the stimuli Z, V _{1 5} V ₂ , V ₃ , V ₄ , from the reference amount, so that a simple evaluation of the EEG measurement data DU ₂ , U ₃ , U _4, the each stimulus S _{1 fifth} S ₂ , S ₃ , S ₄ , S _{5 are} assigned, is guaranteed.

5 shows a test set of five stimuli Si, S ₂ , S ₃ , S ₄ , S ₅ , which in the exemplary embodiment consists of five images, the stimuli S _{1 5} S ₂ , S ₃ , S ₄ , S _{5 of} the test set partially or wholly different from the stimuli Z, V _{1 5} V ₂ , V ₃ , V _{4 of} the reference quantity. For advertising purposes, five images of the same food in different processing form are used in the embodiment to examine the quality of the images on advertising effectiveness. In the stimuli S _{1 5} S ₂ , S ₃ , S ₄ , S _{5 of} the test amount In the example shown, this is five pictures of chocolate-containing food. In the exemplary embodiment, the stimulus Si used is the image of a bar of chocolate used in the reference set of stimuli as target stimulus Z, while the remaining stimuli S ₂ , S ₃ , S ₄ , S _{5 are} not part of the reference set of stimuli. Si could also be a different picture.

After the application of the stimuli Si, S ₂ , S ₃ , S ₄ , S ₅ from the test quantity, the E EG is described in the same way as described above for the stimuli Z, V _{1 5} V ₂ , V ₃ , V _{4 of} the reference quantity Measured data Ui, U ₂ , U ₃ , U _{4 of} the subject 1 and created for each stimulus Si, S ₂ , S ₃ , S ₄ , S _5, a feature vector. In the example, each stimulus S ₁ S ₂ , S ₃ , S ₄ , S _{5 was} applied eight times from the test quantity to the subject 1, so that for each stimulus S _{1 5} S ₂ , S ₃ , S ₄ , S _{5 have} eight features Vectors are available. The number of applications could also be higher or lower.

6 shows by way of example the feature vectors of the stimuli Si, S ₂ , S ₃ , S ₄ , S _{5 of} the test set plotted in a two-dimensional feature space. It can be seen that the individual feature vectors associated with a stimulus S ₁ S ₂ , S ₃ , S ₄ , S ₅ are to be distinguished as five groups of feature vectors in the illustrated two-dimensional feature space.

Subsequently, the discriminating function F is applied to each feature vector of each stimulus Si, S ₂ , S ₃ , S ₄ , S _{5 of} the test set, and thus a measure of the likelihood of coincidence of each stimulus Si, S ₂ , S ₃ , S ₄ , S _{5 of} the test set with the target stimulus Z of the reference set determined. Based on this determined measure of the probability of a match, a ranking of the perception intensity of the individual stimuli Si, S ₂ , S ₃ , S ₄ , S ₅ from the test set is finally established.

As an alternative to the determination of a dimension value for establishing the ranking of the perception intensity of the individual stimuli S ₁ S ₂ , S ₃ , S ₄ , S ₅ from the test set, the distance to the discriminating line indicated by the distinguishing function (F) can also be used as the measured value Discrimination hyperplane of each stimulus S _{1 5} S ₂ , S ₃ , S ₄ , S ₅ are used.

In the example shown in FIG. 6, it can be seen that the feature vectors of the stimulus S _{1 5} corresponding to the target stimulus Z of the reference set have a similar position in the feature space in the feature space as the feature vectors of the target Stimulus Z in FIG. 4. The stimulus Si therefore has the largest value for the probability of matching the target stimulus Z of the reference quantity and is therefore recognized as the stimulus with the highest perceptual intensity in the subject 1. In the example, stimulus S ₅ has the measure value for the second largest probability of a match with the target stimulus Z and thus has the second highest perceptual intensity in the subject 1. Stimulus S ₂ has the least likelihood measure of compliance and therefore corresponds to the stimulus with the lowest perceptual intensity in subject 1.

It can also be provided that an average of the measured values from all applications of a single stimulus S ₁ S ₂ , S ₃ , S ₄ , S _{5 of} the test set for the generation of the ranking of the perception intensity of the individual stimuli S ₁ S ₅ S ₂ , S ₃ , S ₄ , S _{5 is} used. As stimulus S ₁ S ₂ , S ₃ , S ₄ , S ₅ from the test amount with the highest perceptual intensity in the subject 1, for example, that stimulus S ₁ S ₅ S ₂ , S ₃ , S ₄ , S ₅ with the measure of the highest Probability of matching with the target stimulus Z of the reference set determined.

In a second embodiment of a method according to the invention, without predetermining target and comparison stimuli for determining the ranking of the perception intensity of stimuli Si, S ₂ , S ₃ , S ₄ , S ₅ from a test set of stimuli, first the individual stimuli Si, S ₂ , S ₃ , S ₄ , S _{5 applied} from the test amount to the subjects 1.

As already described above, the individual brain waves emitted by the subject 1 are evaluated by an EEG processing device 2 and the reaction of the subject 1 determined by the stimuli Si, S ₂ , S ₃ , S ₄ , S ₅ caused or be determined with this time-related EEG measurement data Ui, U ₂ , U ₃ , U _{4 of} the subject 1 and the respective stimulus Si, S ₂ , S ₃ , S ₄ , S _{5 are} assigned. From the EEG measurement data DU ₂ , U ₃ , U _{4 of} the subject 1 assigned to the respective stimulus, an evoked potential is then determined as the mean value of the EEG measurement data DU ₂ , U ₃ , U ₄ .

FIG. 7 schematically shows the evoked potentials determined for the stimuli Si, S ₂ , S ₃ , S ₄ , S _{5 of} the test quantity shown in FIG. 5. In order to determine the ranking of the perception intensity of the stimuli S ₁ S ₂ , S ₃ , S ₄ , S ₅ based on the associated evoked potentials, a further dimensional value is determined, which in the example corresponds to the amplitude of the evoked potentials. The stimulus S ₁ corresponds to ₅ S ₂ , S ₃ , S ₄ , S ₅ the test set with the highest determined amplitude of the associated evoked potential to the stimulus Si, S ₂ , S ₃ , S ₄ , S ₅ with the highest perceptual intensity.

In the example shown in FIG. 7, the stimulus Si has the highest amplitude, so that stimulus Si is perceived by the subject 1 with the highest intensity. Stimulus S ₂ has the second highest amplitude so that the stimulus S _{2 is} perceived by subject 1 with the second highest intensity. Stimulus S ₂ is perceived by subject 1 with the lowest intensity, and the associated evoked potential therefore has the lowest amplitude of all stimuli Si, S ₂ , S ₃ , S ₄ , S ₅ from the test set.

Alternatively, it can also be provided that the measure value for determining the order of priority of the perception intensity of the stimuli S ₁ S ₂ , S ₃ , S ₄ , S _{5 is determined} from the test quantity according to the area under the curve described by the evoked potential, and / or the dimension value is based on the latency of the evoked potential associated with the respective stimulus S ₁ S ₂ , S ₃ , S ₄ , S ₅ . In this case, for example, that stimulus S ₁ S ₂ , S ₃ , S ₄ , S _{5 has} the highest perceptual intensity in the subject 1, which has the largest area under the curve of the associated evoked potential or its latency of the associated potential is the shortest. That is to say the delay time, that is to say the period between the application of the stimulus S ₁ S ₂ , S ₃ , S ₄ , S ₅ and the occurrence of a response occurring in the course of the curve of the associated evoked potential to the application of the stimulus S ₁ , S ₂ , S ₃ , S ₄ , S ₅ is the shortest.

In a third embodiment of a method according to the invention, the first and the second embodiment are combined to determine the ranking of the perception intensity of stimuli Si, S ₂ , S ₃ , S ₄ , S ₅ from a test set of stimuli. A first measured value is first determined according to the first embodiment of the invention and then separately a second measured value according to the second embodiment of the invention: the first measured value gives the probability of a match of each individual stimulus S ₁ S ₂ , S ₃ , S ₄ , S ₅ from the test set of stimuli with a target stimulus Z to a reference set of stimuli. The second measure value is determined based on the evoked potentials associated with the respective stimuli S ₁ S ₂ , S ₃ , S ₄ , S ₅ from the test set.

As the next step, a common dimensional value is determined from the two dimensional values, and the stimulus S ₁ S ₂ , S ₃ , S ₄ , S ₅ from the test quantity is determined as the stimulus with the highest intensity of perception in the subject 1, for whom both the standard value for the highest agreement with the target stimulus Z of the reference quantity, and, for example, the highest amplitude of the associated evoked potential was found.

This method variant advantageously leads to particularly reliable statements about the ranking of the perception intensity of the stimuli Si, S ₂ , S ₃ , S ₄ , S ₅ from the test set in the subject 1, since several measure values are combined and possible blurring in the determination of each individual measure can be compensated in such a way.

In all the above-described embodiments of a method according to the invention, instead of a temporally successive application of the individual stimuli Z, V ₁ ... V _n from the reference set of stimuli or the individual stimuli S _! , S _m from the test set of stimuli, alternatively, a simultaneous application of multiple stimuli Z, V ₁ .., V _n or S ₁ .., S _m may be provided.

In this case, it can be ascertained, for example, by detecting the line of sight or the eye movement of the subject 1, on soft of the stimuli Z, ν ₁ .., ν _η or S _! , ..., S _m directed the eyes of the subject. 1 The detection of the eye movement starts the evaluation of the individual emitted by the subject 1, and brain waves from these brain waves, the stimulus with that Z, V, ..., V _n and Si, ..., S _m temporally related EEG data Ui, U ₂ , U ₃ , U ₄ all EEG channels or EEG electrodes 21 -24 created. A measure value determined on the basis of these data as described above is assigned to the stimulus Z, V,..., V _n or Si,..., S _n , respectively, to which the eyes were directed during the recording.

Alternatively, it can also be provided that each stimulus Z, V,..., V _n or Si,..., S _{m is applied} multiple times to the subject 1, the application of a single stimulus Z,

or Si, ..., S _m need not necessarily take place several times in succession, but also another stimulus Z, V ₁ .., V _n or S ₁ .., S _m or several different stimuli Z, ν ₁ .. , ν _η or S ₍ S _m can be alternately applied.

For each application of a stimulus Z, ν ₁ .., ν _η or S ₁ .., S _m is a partial feature vector of the time with the stimulus Z, ν ₁ .., ν _η and S ₍ S _n _m-related EEG data DU _2, U _3, U ₄ determines all EEG channels. from all partial Merkmals- vector of the same stimulus Z, V ₁ .., V or S ^ ... ^ is a subsequently Feature vector or a feature matrix for the image created, in particular by all sub-feature vectors in any order as columns of the feature matrix are strung together, so that the lines of the feature matrix corresponding information from different applications of a stimulus Z, Μ ^,.,., Μ ^ or Si, ..., S _m . contain.

As stimuli Z, Μ ^,.,., Μ ^ for the reference set of stimuli or as stimuli Si,..., S _m for the test set of stimuli, as in the examples described above, visual stimuli, in particular images, in question. Alternatively, auditory stimuli or sounds in frequencies audible to a human, in particular sequences of sounds, vibrotactile stimuli or electrical stimuli on different body parts, or the application of different words on the subjects 1 by auditioning and / or announcements and / or displays, may be provided ,

In the application of stimuli Z, ν ₁ .., ν _η from the reference amount or stimuli S ₁ .., S _m from the test amount is a short application time especially with an application time shorter than 2000 ms, preferably shorter than 500 ms, and / / or greater than 100 ms, particularly advantageous. With a shorter duration of application of the stimuli, the sharply demarcated positive rash occurring in the course of the associated evoked potentials as a so-called P300 modality is clearly recognizable, so that the associated amplitude or the area under the curve or else the latency is easier to determine than at longer application time. When applying individual words, therefore, a number of letters smaller than 50 is also advantageous.

As practical fields of application for all methods according to the invention, for example, investigations in the field of marketing for the acceptance of company logos or product design in a selected target group, but also medical issues in patients with nutritional disorders for the determination of foods for which there is an incompatibility in the patient in question.

Claims

claims

1 . Method for determining the ranking of the perception intensity of stimuli (Si, ..., S _n ) from a test set of stimuli in a subject (1) by means of a brain-computer interface (20), wherein a reference set of stimuli (Z, V ₁ .., V _n ) is composed of at least one target stimulus (Z) and a predetermined number of comparison stimuli,

being in a training phase

a) the individual stimuli (Z, V,..., V _n ) from the reference quantity are applied to the subject (1),

b) wherein after the application of each stimulus (Z, V ₁ .., V _n ) from the reference amount, the response of the subject (1) is determined by the stimulus (Z, V ₁ .., V _n ) caused or the be determined with this time-related EEG measurement data (Ui, ..., U _n ) of the subject (1), and these EEG measurement data (U ₁ .., U _n ) the respective stimulus (Z, V ₁ . ., V _n ), wherein for each stimulus (Z, V, ..., V _n ) at least one feature vector from the EEG measurement data (U ₁ .., U _n ) of all EEG channels is created and

c) wherein the feature vectors of the stimuli (Z, V ₁ .., V _n ) thus obtained are subjected to a classification analysis from the reference set, a distinguishing function (F) for delimiting the set of feature vectors of the comparison stimuli

is determined from the set of feature vectors of the target stimulus (Z), the discrimination function indicating whether a stimulus (Z, V, ..., V _n ) is a target stimulus (Z) or a comparison stimulus

is, and being in an investigation phase

d) a test amount of stimuli (Si, ..., S _m ) is applied to the subjects (1), wherein the test amount at least partially or completely different from the stimuli (Z, V, ..., V _n ) of the reference amount Comprises stimuli (Si, ..., S _m ),

e) wherein after application of each stimulus (Si, ..., S _m ) of the test amount in the same manner as in step b) the EEG measurement data (U ₁ .., U _n ) of the subject (1) are determined and based on the EEG measurement data (U ₁ .., U _n ) for each stimulus (S ₁ .., S _m ) first a feature vector is created and

f) wherein each of the distinguishing function (F) is applied to the feature vector of each stimulus (S ₁ .., S _m ) of the test set and such a first

Measure for the match of each stimulus (S ₍ S _m ) of the test set with the

Target stimulus (Z) of the reference quantity is determined, and g) wherein a ranking of the perceptual intensity of the stimuli (S ₁ .., S _m ) of the test set corresponding to the first measure of the match with the target stimulus (Z) of the reference set is established.

2. Method according to claim 1, characterized in that the feature vectors of the stimuli of the reference quantity are subjected to one of the following types of classification analysis:

- Discriminant analysis, in particular linear discriminant analysis,

- Support vector machines,

- neural networks,

- other discrimination functions.

3. The method according to claim 1 or 2, characterized in that the stimulus (S ₁ .., S _m ) of the test set with the measure of the highest agreement with the target stimulus (Z) of the reference amount of the stimulus (S ^ - _^ S _m ) corresponds to the highest perceptual intensity.

4. The method according to claim 1 or 2, characterized in that the dimension value indicates the distance from a by the distinguishing function (F) specified discrimination line or discrimination level.

5. The method according to any one of the preceding claims, characterized in that each stimulus (Si, ..., S _m ) from the test amount is repeatedly applied to the subject (1) and that in the determination of the order of priority of the perception intensity of the mean value of the measured values From all applications of each stimulus (Si, ..., S _m ) is used or that the measures from all applications of each stimulus (Si, ..., S _m ) are used.

6. The method according to any one of the preceding claims, characterized in that in the training phase, a measure of the probability of delimiting the set of feature vectors of the comparison stimuli (V ..., V _n ) of the set of feature vectors of Target stimulus (Z) is determined by the distinguishing function (F), in particular that when falling below a predetermined threshold probability or threshold accuracy of the delimitation process is aborted.

7. The method according to any one of the preceding claims, characterized in that repeated in the training phase

according to step a) and b) according to claim 1 feature vectors for the individual stimuli (Z, V, ..., V _n ) of the reference set are created, the feature vectors of each stimulus (Z, V, ... , V _n ) of the reference set from all repetitions are subjected to a classification analysis, and

- a distinguishing function (F) for delimiting the set of feature vectors of the comparison stimuli (V ^ -. _^ V _n ) from the set of feature vectors of the target stimulus (Z) is determined, and

that after each repetition or in each case after a number of repetitions, the distinguishing function (F) is applied to the feature vector of each individual stimulus (Z,... _n ) of the reference quantity and it is checked in such a way as to determine whether the quantity of feature set obtained Vectors of the comparison stimuli (V ..., V _n ) from the set of feature vectors of the target stimulus (Z) of a given accuracy are sufficient.

8. A method for determining the ranking of the perception intensity of stimuli (S ₁ .., S _m ) from a test set of stimuli in a subject (1) by means of a brain-computer interface (20), characterized in that

a) the individual stimuli (Si, ..., S _m ) are applied from the test quantity to the subject (1),

b) wherein after the application of each stimulus (Si, ..., S _m ) from the test set the reaction of the subject (1) is determined by the stimulus (Si, ..., S _m ) caused or with this temporally related EEG measurement data (Ui, ..., U _n ) of the subject (1) are determined with a predetermined number of EEG channels, and these EEG measurement data (Ui, ..., U _n ) the respective Stimulus (Si, ..., S _n ) are assigned, with an evoked potential for each stimulus as an average of the EEG measurement data (Ui, ..., U _n ) is determined from the predetermined number of EEG channels, and

c) where the order of the perception intensity of the stimuli (S ₍ S _m ) of the stimuli

Test quantity is determined from a second measure, which is determined in particular according to the amplitude of the evoked potentials derived from the EEG measurement data (U ₁ .., U _n ), wherein a higher amplitude indicates a higher perceptual intensity.

9. The method according to claim 8, characterized in that that stimulus (S ^ -. _^ S _n ) of the test set with the highest determined amplitude of the associated evoked potential corresponds to the stimulus (S ₁ .., S _m ) with the highest perceptual intensity.

10. The method according to any one of claims 8 or 9, characterized in that the ranking of the intensity of perception of the stimuli (Si, ..., S _m ) from the test amount to the area under the evoked potential curve, wherein a large area under the Curve indicates a high perceptual intensity, and / or after the latency of the evoked potential, with a short latency indicating a high perceptual intensity is determined.

1 1. Method according to one of claims 1 to 7, characterized in that in the examination phase for determining the ranking of the perception intensity of the stimuli (S ₁ .., S _m ) from the test amount a first Maßwert according to claim 1 and additionally a second Maßwert according to claim 8 be determined,

wherein for determining the order of priority of the perceptual intensity of the stimuli (S ₁ .., S _m ), a common measured value is determined from the two determined dimensional values.

12. The method according to claim 11, characterized in that the common dimension value indicates the greater the intensity of perception, the greater the index of the first measure indicated agreement of the stimulus (Si, ..., S _m ) from the test set with the target stimulus ( Z) is the reference quantity and the greater the intensity of perception indicated by the second measure.

13. The method according to any one of the preceding claims, characterized in that the individual stimuli (Z, V, ..., V _n ) from the reference amount and / or the individual stimuli (Si, ..., S _m ) from the test amount temporally successive on the subjects (1) are applied, with each individual stimulus (Z, V, ..., V _n ) from the

Reference quantity and / or to each individual stimulus (S ₍ S _m ) from the test amount followed by an application-free period.

14. A method according to any one of the preceding claims, characterized in that (in a fixed reference time interval prior to the application of each stimulus (Z, V ₁ .., V _n) from the reference amount and / or prior to the application of each stimulus S ₁ .., S _m ) from the test set a voltage offset value is determined and the voltage offset value of the respective stimulus (Z, V ..., V _n ) from the Reference quantity and / or the respective stimulus (S ₁ .., S _m ) from the test set associated EEG measurement data (Ui, ..., U _n ) is subtracted.

15. The method according to any one of the preceding claims, characterized in that for each individual stimulus (Z, V, ..., V _n ) from the reference amount and / or for each stimulus (Si, ..., S _m ) the test amount is given an application duration, in particular, that for all stimuli an equally long application time is specified, and / or

in that a number of repetitions for each individual stimulus (Z, V,..., V _n ) is given from the reference quantity and / or for each individual stimulus (Si,..., S _m ) from the test set, in particular all stimuli are repeated with the same number of repetitions, and / or

that the duration of the application-free period after each individual stimulus (Z,

V, ..., V _n ) from the reference quantity and / or after each individual stimulus (S ₍ S _m ) from the test set is specified, in particular that for all / before all stimuli an equal duration of the application-free period is specified.

16. The method according to any one of the preceding claims, characterized in that the stimuli (Z, V ..., V _n ) from the reference amount and the stimuli (S ₁ .., S _m ) from the test amount stimuli of at least one of the following types include:

- visual stimuli, in particular images, in particular with a display duration shorter than 2000 ms, preferably shorter than 500 ms, and / or greater than 100 ms, which are presented to the subject (1) by means of a screen, and / or

auditory stimuli or sounds in human audible frequencies, in particular sequences of tones, preferably with a total duration shorter than 2000 ms, preferably shorter than 500 ms, and / or greater than 1 00 ms, wherein the respective sounds the subject (1) played be, and / or

- Vibrotaktile stimuli on different body parts, in particular with a duration shorter than 2000 ms, preferably shorter than 500 ms, and / or greater than 1 00 ms, which are applied to the subject (1) by means of vibration units, and / or

electrical stimuli on different body parts, in particular with a duration shorter than 2000 ms, preferably shorter than 500 ms, and / or greater than 1 00 ms, which are applied to the subject (1) by means of electrical stimulators, and / or the application of different words, in particular names, preferably with a duration shorter than 2000 ms, preferably shorter than 1000 ms, and / or greater than 100 ms, the application being that the respective words are played to the subject (1) and / or predicted and / or displayed become.

17. Apparatus for determining the order of the intensity of perception of stimuli (Si,..., S _n ) from a test quantity of stimuli in a subject (1) comprising an electrode cap, comprising a number of EEG electrodes (21, 22, .. .)

- An electrode hood downstream of the brain-computer interface (20), wherein the brain-computer interface (20) is adapted to each of the EEG electrodes (21, 22, ...) to measure voltages and measurement results as EEG measurement data (Ui, ..., U _n )

- A the brain-computer interface (20) downstream control unit (30) and

- at least one of the control unit (30) downstream stimulation unit (40) wherein in the control unit (30) control instructions for the stimulation unit (40) for applying a reference amount of stimuli (Z, V ₁ .., V _n ) composed of at least one target Stimulus (Z) and a predetermined number of comparison stimuli (V ₁ .., V _n ) and a test set of stimuli (S ₁ .., S _m ) are deposited, the test amount at least partially or entirely of the stimuli (Z , V ₁ .., V _n ) of the reference set comprises different stimuli (S ₍ S _m ), and

wherein the control unit (30) is designed to

in a training phase

to control the stimulation unit (40) and to apply the individual stimuli (Z, V, ..., V _n ) from the reference quantity to the subject (1) via the stimulation unit (40),

the EEG measurement data (Ui,..., U _n ) provided by the brain-computer interface (20), caused by the stimulus (Z, V,..., V _n ) or the temporally related EEG measurement data (Ui,..., U _n ) of the subject (1) to assign each stimulus (Z, V, ..., V _n ) from the reference set to the respective stimulus (Z, V, ..., V _n ) after the application and thus to determine the response of the subject (1) .

for each stimulus (Z, V, ..., V _n ) at least one feature vector from the EEG measurement data (Ui, ..., U _n ) of all EEG channels to create and

to subject the feature vectors of the stimuli (Z, ν ₁ ..., ν _η ) thus obtained to a classification analysis from the reference set and a distinguishing function (F) to delimit the set of feature vectors of the comparison stimuli (V ₁ . Vn) from the set of feature vectors of the target stimulus (Z), the distinguishing function indicating whether a stimulus (Z, V, ..., V _n ) is a target stimulus (Z) or a comparison stimulus Stimulus (V ..., V _n ), and wherein the control unit (30) is adapted to

in an investigation phase to control the stimulation unit (40) and to apply the test quantity of stimuli (S ₍ S _m ) to the subject (1) via the stimulation unit (40),

the EEG measurement data (Ui,..., U _n ) provided by the brain-computer interface (20), caused by the stimulus (Si,..., S _m ) or the temporally related EEG measurement data (Ui,..., U _n ) of the subject (1 ) to assign each stimulus (Si, ..., S _m ) from the test quantity to the respective stimulus (Si, ..., S _m ) after the application and thus determine the response of the test person (1),

for each stimulus (Si, ..., S _m ) to generate at least one feature vector from the EEG measurement data (Ui, ..., U _n ) of all EEG channels,

apply the distinguishing function (F) to the feature vector of each individual stimulus (S ^ -. _^ S _m ) of the test set and so obtain a first measure of the fit of each stimulus (S ,, ... ^) of the test set with the target Stimulus (Z) to determine the reference quantity, and

to create a ranking of the perceptual intensity of the stimuli (S ₍ S _m ) of the test set corresponding to the first measure of agreement with the target stimulus (Z) of the reference set.

18. Device according to claim 17, characterized in that the control unit (30) is adapted to subject the feature vectors of the stimuli of the reference set to one of the following types of classification analysis:

- Discriminant analysis, in particular linear discriminant analysis,

- Support vector machines,

- neural networks,

- other discrimination functions.

19. The apparatus of claim 17 or 18, characterized in that the control unit (30) is adapted to that stimulus (Si, ..., S _m ) of the test set with the measure value for the highest match with the target stimulus (Z ) of the reference set as the stimulus (S ₁ .., S _m ) with the highest perceptual intensity.

20. Device according to claim 17 or 18, characterized in that the control unit (30) is designed to determine the distance from a discriminating line or discrimination level specified by the distinguishing function (F) as a dimensional value.

21. Device according to one of the preceding claims, characterized in that the control unit (30) is designed to control the stimulation unit (40), each stimulus (Si, ..., S _m ) from the test amount multiple times to the subject (1) apply and

in the determination of the ranking of the perception intensity, the average of the measurement values from all applications of each individual stimulus (Si, ..., S _m ) or the measurement values from all applications of each individual stimulus (Si, ..., S _m ).

22. Device according to one of the preceding claims, characterized in that the control unit (30) is adapted, in the training phase, a measure of the probability of delimiting the set of feature vectors of the comparison stimuli (V ₁ .., V _n ) from the set of feature vectors of the target stimulus (Z) by the discriminating function (F),

In particular, the control unit (30) is designed to control the stimulation unit (40) when it falls below a predetermined threshold probability or threshold accuracy of the delimitation and to issue a warning via the stimulation unit (40), in particular also to terminate the training phase.

23. Device according to one of the preceding claims, characterized in that the control unit (30) is adapted to repeated in the training phase:

to apply the stimuli (Z, V,..., V _n ) from the reference quantity to the subject (1) via the stimulation unit (40),

- Create feature vectors for the individual stimuli (Z, V, ..., V _n ) of the reference set

- subject the feature vectors of each reference stimulus (Z, V, ..., V _n ) to all the repetitions of a classification analysis,

to determine a distinguishing function (F) for delimiting the set of feature vectors of the comparison stimuli (V ..., V _n ) from the set of feature vectors of the target stimulus (Z), and

after each repetition, apply the distinguishing function (F) to the feature vector of each individual stimulus (Z, V ₁ ..., V _n ) of the reference set and to check whether the obtained delimitation of the set of feature vectors of the comparison stimuli (V ₁ .., V _n ) of the set of feature vectors of the target stimulus (Z) satisfies a predetermined accuracy.

24. An apparatus for determining the order of magnitude of the perception intensity of stimuli (Si,..., S _n ) from a test set of stimuli in a subject (1) comprising an electrode cap comprising a number of EEG electrodes (21, 22, .. .)

- A the brain-computer interface (20) downstream control unit (30) and

at least one stimulation unit (40) connected downstream of the control unit (30) is characterized in that

that in the control unit (30) control instructions for the stimulation unit (40) for applying a test amount of stimuli (S ₁ .., S _m ) are stored, and

the control unit (30) is designed to

to control the stimulation unit (40) and to apply the individual stimuli (S ₁ .., S _m ) from the test set via the stimulation unit (40) to the subject (1) provided by the brain-computer interface (20), from Stimulus (S ₍ S _m ) caused or the temporally related EEG measurement data (Ui, ..., U _n ) of the subject (1), after the application of each stimulus (SL - ^ SJ from the

Allocate the test quantity to the respective stimulus (S ₍ S _m ) and thus determine the response of the subject (1),

to determine the ranking of the perception intensity of the stimuli (Si,..., S _m ) of the test set, to determine a second measured value, in particular according to the amplitude of the evoked potentials derived from the EEG measurement data (Ui,..., U _n ) , where a higher amplitude indicates a higher perceptual intensity.

25. The device according to claim 24, characterized in that the control unit (30) is adapted to those stimulus (Si, ..., S _n) of the test set with the highest determined amplitude of the associated evoked potential (as the stimulus _S1. ., S _m ) with the highest perceptual intensity.

26. Device according to one of claims 24 or 25, characterized in that the control unit (30) is adapted to the ranking of the perception intensity of the stimuli (S ₍ S _m ) from the test set

to determine the area under the evoked potential curve, where a large area under the curve indicates a high perceptual intensity, and / or to determine the latency of the evoked potential, with a short latency indicating a high perceptual intensity.

27. Device according to one of claims 1 7 to 23, characterized in that the control unit (30) is adapted, in the investigation phase for determining the order of priority of the perception intensity of the stimuli (Si, ..., S _m ) from the test amount first measure value by applying the discriminating function (F) to the feature vector of each stimulus (Si, ..., S _m ) of the test set and additionally a second measure, in particular according to the amplitude of the from the EEG measurement data (Ui, .. ., U _n ) derived evoked potentials to determine

and to determine the order of priority of the intensity of perception of the stimuli (Si,..., S _m ) to determine a common measure value from the two determined dimensional values.

28. Method according to claim 27, characterized in that the control unit (30) identifies a greater perception intensity of the common dimension value, the greater the index of the stimulus (S ₍ S _m ) of the test quantity with the target stimulus indexed by the first measurement value ( Z) is the reference quantity and the greater the intensity of perception indicated by the second measure.

29. The method according to any one of the preceding claims, characterized in that the control unit (30) is adapted to control the stimulation unit (40), the individual stimuli (Z, V, ..., V _n ) from the reference amount and / or to apply the individual stimuli (Si,..., S _m ) from the test quantity in succession to the subject (1), and to each individual stimulus (Z, V,..., V _n ) from the reference quantity and / or to follow each single stimulus (Si, ..., S _m ) from the test quantity an application-free period.

30. The method according to any one of the preceding claims, characterized in that the brain-computer interface (20) comprises a voltage-offset unit, wherein the voltage-offset unit is adapted to a predetermined time reference interval before the application of a each stimulus (Z, V ₁ .., V _n ) from the reference quantity and / or before the application of each stimulus (S ₁ .., S _m ) from the test amount to determine a voltage offset value and the voltage offset value of the the respective stimulus (Z, V ..., V _n ) from the reference quantity and / or the EEG measured data (U ₁ .., U _n ) assigned to the respective stimulus (S ₁ .., S _m ) from the test set ,

31. Method according to one of the preceding claims, characterized in that the control unit (30) for specifying an application duration for each individual Stimulus (Z, V ₁ .., V _n ) from the reference amount and / or for each stimulus (Si, ..., S _m ) is formed from the test amount, in particular, that the control unit (30) for setting an equal long application time is designed for all stimuli, and / or

that the control unit (30) for presetting a number of repetitions for each individual stimulus (Z, V, ..., V _n ) from the reference amount and / or for each individual stimulus (Si, ..., S _m ) from the Test set is formed, in particular, that the control unit (30) is designed to specify an equal number of repetitions for all stimuli, and / or

in that the control unit (30) is configured to prescribe a duration of the application-free period after each individual stimulus (Z, V ..., V _n ) from the reference quantity and / or after each individual stimulus (S ₍ S _m ) from the test quantity, in particular, that the control unit (30) is designed to specify an equal length of the application-free period after all stimuli.

32. Device according to one of the preceding claims, characterized in that the stimulation unit (40) is designed for the application of stimuli of at least one of the following types:

visual stimuli, in particular images, in particular with a display duration shorter than 2000 ms, preferably shorter than 500 ms, and / or greater than 1 00 ms, and / or auditory stimuli or sounds in human audible frequencies, in particular sequences of sounds, preferably with a total duration shorter than 2000 ms, preferably shorter than 500 ms, and / or greater than 1 00 ms, and / or

- Vibrotaktile stimuli on different body parts, in particular with a duration shorter than 2000 ms, preferably shorter than 500 ms, and / or greater than 1 00 ms, and / or

electrical stimuli to different body parts, in particular with a duration shorter than 2000 ms, preferably shorter than 500 ms, and / or greater than 1 00 ms, and / or

- The application of different words, in particular names, preferably with a duration shorter than 2000 ms, preferably shorter than 1 000 ms, and / or greater than 100 ms.